CN108048869A - A kind of Ni-based active electrode material of embedded ruthenium hafnium composite oxides and preparation method thereof - Google Patents

Abstract

The invention provides a nickel-based active electrode material embedded in a ruthenium-hafnium composite oxide and a preparation method thereof. The average particle diameter of the ruthenium-hafnium composite oxide is 12 nm, and the molar ratio of Hf to (Hf+Ru) is (0.35～0.45):1. The invention adopts the composite electroplating method to simultaneously deposit nickel and ruthenium-hafnium composite oxides to obtain nickel-based active electrode materials embedded in the ruthenium-hafnium composite oxides. The obtained material has excellent hydrogen evolution activity, and the preparation method is simple, the operability is strong, the raw material is easily obtained, and the cost is low.

Description

A nickel-based active electrode material embedded in ruthenium-hafnium composite oxide and its preparation method

technical field

The invention belongs to the field of electrode materials applied to electrochemistry and energy industry, and specifically relates to an electrode material with high catalytic performance and a preparation method thereof.

Background technique

After the advent of electrodes containing noble metal oxides in 1967, it was found that such oxides had very high electrocatalytic activity, so they were called active oxide materials, or simply active materials. The most superior active material is ruthenium-containing oxides. A large number of studies have found that the comprehensive performance of ruthenium-containing anode materials can not only be improved by doping non-noble metal elements, but also the production cost of ruthenium-containing anodes can be significantly reduced, so that ruthenium-containing composite oxides It is widely used in many electrochemical industries. The application of the active anode greatly improves the chlorine and oxygen evolution activities of the electrode material and reduces the power consumption. Compared with anode materials, the research on cathode materials is relatively weak, and nickel metal or titanium metal with low electrocatalytic activity and stability are still used as cathode materials in many occasions, which seriously restricts the related electrochemical industry fields (including chlor-alkali industry, chlorine salt industry, pharmaceutical industry and new energy industry, etc.).

Twenty years ago, foreign experts discovered that adding more active components to nickel metal to form a mixture can significantly increase the activity of cathode materials (see "Ni+RuO2 co-deposited electrodes for hydrogen evolution", "Electrochemical Acta", 2000 , 45, pp. 4195-4202). After that, the active cathode material of nickel-based ruthenium dioxide (Ni+RuO ₂ ) was successfully developed in the electrochemical industry, that is, the unit oxide RuO ₂ was embedded in nickel metal. However, so far, there have been no new breakthroughs in how to design cathode materials with intercalated structures and how to introduce doping elements to improve the catalytic activity and corrosion resistance of intercalated bodies. This is in line with the continuous progress of anode materials. contrast.

To this end, our scientific research team presided over the National Natural Science Foundation of China project. On the one hand, a series of studies were conducted on the cathode behavior of RuO ₂ -containing composite oxides that can be made into intercalated bodies (see "Preparation of Ru-Mn oxide-coated titanium cathode and hydrogen evolution performance", "Metal Heat Treatment", 2009, 34(11), 36-39 pages), on the other hand, an in-depth study was conducted on the relevant mechanism of anode materials with embedded structures (see "Adding a Spinodal Decomposition Retarder: An Approach to Improving Electrochemical Properties of Ruthenium–Tin ComplexOxides", Journal of Electrochemical Society, 2014, 161(10), pp. E119-E127). Through systematic analysis and research, it is found that only a few kinds of doped _RuO2 are suitable as active intercalators for cathode materials. Among them, adding a certain content of mixed oxides of hafnium can prepare cathode active intercalators, so as to develop new nickel-based composite oxide active cathode materials that can be adapted to acidic media.

Contents of the invention

The object of the present invention is to provide a nickel-based active electrode material embedded in ruthenium-hafnium composite oxide and its preparation method. Low.

To achieve the above object, the present invention adopts the following technical solutions:

A nickel-based active electrode material embedded in a ruthenium-hafnium composite oxide. The ruthenium-hafnium composite oxide can be prepared by conventional thermal decomposition or co-deposition methods, wherein the molar ratio of Hf to (Hf+Ru) is (0.35-0.45 ): 1. The average particle size of the ruthenium-hafnium composite oxide is 12 nm.

The preparation method of the nickel-based active electrode material embedded in the ruthenium-hafnium composite oxide is to degrease the nickel substrate, etch it in 6mol/L sulfuric acid aqueous solution for 1 hour, rinse with deionized water, dry, and then It is immersed in the plating solution, and electroplating is carried out under the condition of stirring. During this process, the pH value of the plating solution is controlled at 4.4-4.6, the temperature of the plating tank is 48 ℃, the current density is 40mA·cm ^-2 , and the electricity is 110 C·cm ^{- 2} , that is to make a nickel-based active electrode material embedded in ruthenium-hafnium composite oxide;

The nickel substrate is industrial pure nickel, nickel mesh or nickel plate; the plating solution contains nickel sulfate hexahydrate 1.2 mol/L, nickel chloride hexahydrate 0.18 mol/L, boric acid 0.42 mol/L, ruthenium and hafnium compound Oxide 30g/L.

Significant advantage of the present invention:

a) The present invention embeds ruthenium-hafnium composite oxide (Ru _1-x Hf _x O ₂ ) with an average size of 12 nm in the nickel-based material, so that it has a nano-embedded structure that is more suitable for electrocatalysis, and finally obtains a highly dispersed structure Structure and highly evenly distributed active centers, so that its activity is greatly improved compared with traditional nickel-based cathode materials, and it also has superior comprehensive performance than nickel-based ruthenium dioxide materials.

b) The present invention introduces a high proportion of hafnium dioxide into the ruthenium-hafnium composite oxide intercalation body, which can effectively utilize the high corrosion resistance of hafnium dioxide, so that the obtained electrode material has good stability in the hydrogen evolution reaction in acidic medium, Moreover, since hafnium is used to partially replace the noble metal element ruthenium, the production cost is significantly reduced.

c) The preparation method of the nickel-based active electrode material embedded in the ruthenium-hafnium composite oxide of the present invention adopts a Watt-type electroplating method, that is, simultaneously deposits nickel and ruthenium-hafnium composite oxide on the etched pure nickel substrate to obtain Nickel-based active electrode materials embedded in ruthenium-hafnium composite oxides.

d) The nickel-based active electrode material embedded in the ruthenium-hafnium composite oxide obtained in the present invention can be used as a cathode component for electrochemical industries such as chlor-alkali, chlorate, water electrolysis, organic solution electrolysis, supercapacitor, hydrogen storage battery, fuel cell, etc. Especially suitable for hydrogen evolution reaction in acidic medium.

e) The preparation materials of the present invention are simple and easy to obtain, the process is stable, and the conditions for practical and industrial application can be achieved.

Detailed ways

The invention adopts a composite electroplating method to obtain a nickel-based ruthenium-hafnium composite oxide active electrode material with an embedded structure, and the preparation steps of the active electrode material are as follows:

1) Treatment of nickel substrate: Degrease industrial pure nickel, nickel mesh or nickel plate, etch in 6 mol/L sulfuric acid aqueous solution for 1 hour, rinse with deionized water, and dry;

2) Preparation of the plating solution: prepare the plating solution according to the concentrations of nickel sulfate hexahydrate 1.2 mol/L, nickel chloride hexahydrate 0.18 mol/L, boric acid 0.42 mol/L, and ruthenium-hafnium composite oxide 30 g/L; the ruthenium The molar ratio of Hf:(Hf+Ru) in hafnium composite oxide is 0.35～0.45:1;

3) Electroplating: immerse the treated nickel substrate in the plating solution, and perform electroplating under the condition of mechanical stirring; during the electroplating process, the pH value of the plating solution is controlled to be 4.4-4.6, the temperature of the plating tank is 48 ℃, and the current density is 40 mA· cm ^-2 , the electric quantity is 110 C·cm ^-2 , which is to make the nickel-based active electrode material embedded in the ruthenium-hafnium composite oxide.

Three implementation examples of the present invention are described in detail below, but the present invention is not limited thereto.

Example 1

1) Use industrial pure nickel N6 mesh as the nickel substrate, use 10% detergent to degrease, then etch in 50°C, 6 mol/L sulfuric acid aqueous solution for 1 hour, rinse with deionized water, and dry;

2) In a solution containing 1.2 mol/L nickel sulfate hexahydrate, 0.18 mol/L nickel chloride hexahydrate and 0.42 mol/L boric acid, add ruthenium-hafnium composites with an average size of about 12 nm prepared by thermal decomposition. Oxide (Hf:Hf+Ru molar ratio is 0.35:1) 30 g/L to prepare the plating solution;

3) Heat the plating solution to 48°C, adjust the pH of the plating solution to 4.5 with 5 mol/L HCl, and carry out constant current electrodeposition with a current density of 40 mA cm ^-2 under mechanical stirring, and the electric quantity is 110 C· cm ^-2 , which is to make nickel-based active electrode materials embedded in ruthenium-hafnium composite oxides.

An electrochemical workstation was adopted, using a three-electrode system, with a saturated calomel electrode (SCE) as a reference electrode, and an electrolyte of 0.5 MH ₂ SO ₄ solution at 25 °C. The measured Tafel slope of hydrogen evolution of the electrode material is 55 mV·decade ^-1 , indicating that it has significant electrocatalytic activity.

Example 2

1) Use industrial pure nickel N6 mesh as the nickel substrate, use 10% detergent to degrease, then etch in 50°C, 6 mol/L sulfuric acid aqueous solution for 1 hour, rinse with deionized water, and dry;

2) In a solution containing 1.2 mol/L nickel sulfate hexahydrate, 0.18 mol/L nickel chloride hexahydrate and 0.42 mol/L boric acid, add ruthenium-hafnium composites with an average size of about 12 nm prepared by thermal decomposition. Oxide (Hf:Hf+Ru molar ratio is 0.45:1) 30 g/L to prepare the plating solution;

3) Heat the plating solution to 48°C, adjust the pH of the plating solution to 4.6 with 5 mol/L HCl, and carry out constant current electrodeposition with a current density of 40 mA cm ^-2 under mechanical stirring, and the electric quantity is 110 C· cm ^-2 , which is to make nickel-based active electrode materials embedded in ruthenium-hafnium composite oxides.

An electrochemical workstation was adopted, using a three-electrode system, with a saturated calomel electrode (SCE) as a reference electrode, and an electrolyte of 0.5 MH ₂ SO ₄ solution at 25 °C. The measured Tafel slope of hydrogen evolution of the electrode material is 56 mV·decade ^-1 , indicating that it has significant electrocatalytic activity.

Example 3

1) Use industrial pure nickel N6 mesh as the nickel substrate, use 10% detergent to degrease, then etch in 50°C, 6 mol/L sulfuric acid aqueous solution for 1 hour, rinse with deionized water, and dry;

2) In a solution containing 1.2 mol/L nickel sulfate hexahydrate, 0.18 mol/L nickel chloride hexahydrate and 0.42 mol/L boric acid, add ruthenium-hafnium composites with an average size of about 12 nm prepared by thermal decomposition Oxide (Hf:Hf+Ru molar ratio is 0.42:1) 30 g/L to prepare the plating solution;

3) Heat the plating solution to 48°C, adjust the pH of the plating solution to 4.6 with 5 mol/L HCl, and carry out constant current electrodeposition with a current density of 40 mA cm ^-2 under mechanical stirring, and the electric quantity is 110 C· cm ^-2 , which is to make nickel-based active electrode materials embedded in ruthenium-hafnium composite oxides.

An electrochemical workstation was adopted, using a three-electrode system, with a saturated calomel electrode (SCE) as a reference electrode, and an electrolyte of 0.5 MH ₂ SO ₄ solution at 25 °C. The measured Tafel slope of hydrogen evolution of the electrode material is 53 mV·decade ^-1 , indicating that it has significant electrocatalytic activity.

comparative example

1) Use industrial pure nickel N6 mesh as the nickel substrate, use 10% detergent to degrease, then etch in 50°C, 6 mol/L sulfuric acid aqueous solution for 1 hour, rinse with deionized water, and dry;

2) In a solution containing 1.2 mol/L nickel sulfate hexahydrate, 0.18 mol/L nickel chloride hexahydrate and 0.42 mol/L boric acid, add ruthenium dioxide with an average size of about 12 nm prepared by thermal decomposition 30 g/L to prepare the plating solution;

3) Heat the plating solution to 48°C, adjust the pH of the plating solution to 4.6 with 5 mol/L HCl, and carry out constant current electrodeposition with a current density of 40 mA cm ^-2 under mechanical stirring, and the electric quantity is 110 C· cm ^-2 , that is, it is made of ruthenium dioxide-nickel-based active electrode material that does not contain hafnium.

An electrochemical workstation was adopted, using a three-electrode system, with a saturated calomel electrode (SCE) as a reference electrode, and an electrolyte of 0.5 MH ₂ SO ₄ solution at 25 °C. The Tafel slope of hydrogen evolution of the electrode material was measured to be 93 mV·decade ^-1 .

The comparison shows that the novel electrode material proposed by the present invention has remarkable electrocatalytic activity.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (4)

1. a kind of Ni-based active electrode material of embedded ruthenium hafnium composite oxides, it is characterised in that：The ruthenium hafnium composite oxides Middle Hf with（Hf+Ru）Molar ratio be（0.35~0.45）:1.

2. Ni-based active electrode material according to claim 1, it is characterised in that：The ruthenium hafnium composite oxides are put down Equal grain size is 12 nm.

3. a kind of preparation method of the Ni-based active electrode material of embedded ruthenium hafnium composite oxides as described in claim 1, It is characterized in that：By Ni-based material degreasing, etched in the aqueous sulfuric acid of 6 mol/L 1 it is small when after, it is dry with deionized water rinsing, It is then immersed in plating solution, is electroplated under agitation, the pH value that plating solution is controlled during this is 4.4~4.6, coating bath Temperature is 48 DEG C, and current density is 40 mAcm^-2, electricity is 110 Ccm^-2, that is, embedded ruthenium hafnium composite oxides are made Ni-based active electrode material；

Containing 1.2 mol/L of nickel sulfate hexahydrate, 0.18 mol/L of Nickel dichloride hexahydrate, 0.42 mol/L of boric acid, ruthenium in the plating solution Hafnium composite oxides 30g/L.

4. preparation method according to claim 3, it is characterised in that：The Ni-based material is industrial pure ni, nickel screen or nickel plate Material.